What Is Heart Cancer?

Medically Reviewed by Sabrina Felson, MD on February 23, 2024
Written by K.A. Stump-Sutliff
6 min read

Heart cancer is cancer that starts in the cells of your heart. It’s also called primary cardiac cancer. It’s very rare. In fact, almost everything we know about it comes from autopsy studies and case studies, which are published reports discussing people who have this cancer.

Cancer that starts somewhere else in the body and spreads to the heart is much more common. So are heart tumors that are not cancer.

Most primary cardiac cancers (75%) are a kind of cancer called sarcoma. You might hear this called primary cardiac sarcoma. Sarcomas are cancers that start in the soft tissues of the body, like muscles, tendons, blood vessels, and nerves. The rest of the heart cancers are mostly lymphomas and mesotheliomas.

Heart tumors can be benign (noncancerous) or malignant (cancerous). Nearly 80% of heart tumor cases are benign.

Types of malignant heart tumors include:

Sarcoma. This is the most common type of cancerous heart tumor. They mainly affect middle-aged people. There are several types of these, including.

  • Cardiac angiosarcoma: These tumors, made up of abnormal blood vessels, account for nearly 40% of all sarcomas in the heart. They usually begin in the upper right chamber (right atrium) of the heart. These sarcomas grow quickly and have a high risk of spreading (metastasizing) to other areas of the heart and elsewhere in your body. They're more common in men than women.
  • Cardiac rhabdomyosarcoma: This rare type of heart tumor can affect people of all ages. They usually start in the right atrium. But they can also develop in the left atrium and the lower chambers of the heart (ventricles). The tumor can protrude into the chambers of your heart and block blood flow.

Other types of cardiac sarcomas include

  • Pleomorphic sarcoma (also known as malignant fibrous histiocytoma)
  • Undifferentiated sarcoma
  • Leiomyosarcoma
  • Fibrosarcoma
  • Liposarcoma
  • Osteosarcoma

All of these usually develop in the left atrium and may cause heart failure.

Pericardial mesothelioma. This rare type affects men more often than women. It can restrict your heart's motion and cause cardiac tamponade, which is when blood pools in the sac surrounding your heart. It can spread to your spine, nearby soft tissues, and brain. This is a very serious type of cancer.

Primary lymphoma. This extremely rare type of heart cancer commonly affects people with weak immune systems, like those with HIV or AIDS. It tends to grow quickly, which can lead to problems like:

  • Heart failure
  • Irregular heartbeat
  • Cardiac tamponade
  • Superior vena cava syndrome, which happens when blood flow through a large vein in your upper body slows down

 

Myxoma. This noncancerous type makes up nearly half of all heart tumors. It’s 2-4 times more likely to affect women than men. The cause is unknown, but about 10% of the tumors are genetic and passed down through families. Most myxomas develop in the left atrium as a single mass. The only treatment for myxomas is surgery to remove it. This is called a surgical excision.

Fibroma. This type usually affects infants and children. These tumors usually develop on the left side of the heart. They can happen as a result of inflammation. Fibromas can lead to irregular heartbeats (arrhythmias) and sometimes sudden death.

Papillary fibroelastoma. These tumors most often affect the heart valves. They mostly affect older adults, with 60 the average age for diagnosis. A papillary fibroelastoma can lead to an embolism, which happens when bits of the tumor break off and travel through your bloodstream. This can cause a stroke or heart attack.

Rhabdomyoma. This type of benign tumor most often affects infants and children. Around 80% of those who get them have tuberous sclerosis. That's a rare genetic condition in which benign tumors grow in different parts of your body. These tend to develop in the wall of the left lower chamber of your heart (left ventricle). You usually have more than one.

Lipoma. This type of tumor is made of fat cells. They can affect people of all ages. Most don't cause symptoms, but some lead to irregular heartbeats or interfere with blood flow.

Hemangioma. These are made up of abnormal blood vessels. They don't usually cause symptoms, so they're usually found during medical exams done for other reasons.

Little is known about the causes of heart cancer. There are no known risk factors linked to it.

This cancer is most often found in young people. It’s more common in men than women.

Heart tumors can:

  • Affect blood flow to your heart muscle
  • Change blood flow through your heart to the rest of your body
  • Lead to heart failure
  • Damage the system that controls your heart rhythm, causing arrythmias
  • Cause blood clots

Still, heart tumors don’t usually cause symptoms when they’re small. As a tumor grows, symptoms happen depending on:

  • Where it is in the heart
  • How big it is
  • If it has spread and where

Symptoms include:

But these are also symptoms of many heart diseases that are much more common than heart cancer, including:

Many heart cancers grow and spread quickly. They most commonly spread to the lungs, lymph nodes, and liver. This can cause many symptoms, along with those listed above.

Doctors usually see heart tumors on imaging tests like CT scans, heart MRIs, and echocardiogram. These can show the size of the tumor and where it is in your heart.

A heart MRI helps doctors identify tumors that are not cancer and may not need to be removed. It also allows your doctor to look for signs that the tumor might be cancer, such as whether it:

  • Is in the right side of your heart
  • Involves more than one of your heart's chambers
  • Involves the big vessels near your heart
  • Is bigger than 5 centimeters across
  • Has unclear edges

If you have a tumor that looks like this, your doctor may do more tests. For example, if it can be done safely, you might need a biopsy. That's when your doctor removes a tiny piece of the tumor and tests it for cancer. It's the best way to know exactly what kind of tumor you have and how to treat it.

There are not enough people with heart cancer to do clinical trials (studies in people) to find the best treatment. So there are no standard treatments. Instead, treatment is tailored for each person who has heart cancer.

The main treatment is surgery to take out the tumor. But that may not be possible if the tumor is large or in the left side of your heart. Larger tumors may need to be partly removed to help relieve symptoms that affect your heart's function. Chemotherapy and radiation therapy might help you live longer. Your doctor might try targeted therapies that are usually used for sarcomas found in places other than the heart.

Doctors have tried heart transplants, as well as transplants of both the heart and lungs, in a few people with heart cancer. Transplants helped some people live longer but did not work well overall. These surgeries aren't useful for heart cancer that has spread to other parts of the body.

Malignant heart tumors are rarely found early or when they’re small. They often don’t cause symptoms until they’re large and have spread. By that time, they’ve usually caused a lot of heart damage. If doctors can't remove the tumor with surgery, only about 1 out of 10 people with heart cancer are still alive 9-12 months after diagnosis.